The objective of this project is the measurement and cellular localization of cyclic nucleotides in bone surrounding erupting, resorbing and moving teeth. The effects of locally applied hormones and drugs on bone cyclic nucleotides during the above listed processes will be studied. Immuno-histochemical methods have been developed for the localization of cAMP and cGMP in alveolar bone cells. Osteoblasts were found to stain for cAMP but rarely for cGMP. Some periodontal fibroblasts displayed nuclear staining for cGMP. Parathyroid hormone (PTH) administration to cats (500 USP Units/Kg) caused a two-fold increase in jaw bone cAMP concentration and a three-fold increase in cGMP level, within 20 minutes. However, the main elevations in cAMP levels occured in the osteoblastic and osteocytic populations, while cGMP increases were localized in the periodontal fibroblasts and the osteoclasts. Immuno-histochemical localization of cyclic nucleotides in tissues surrounding erupting teeth in kittens will be performed. Calcitonin, PTH, theophylline, imidazole and carbachol will be administered locally near roots of teeth of 1 year old cats. The effect of these agents on alveolar bone cyclic nucleotide concentration and localization will be studied. Anti-cAMP antibodies will be raised in goats and these antibodies, together with rabbit anti-cGMP antibodies, will be used to localize bone cAMP and cGMP in the same tissue section. BIBLIOGRAPHIC REFERENCES: Eckerdal, O., Gustafson, G.T., Davidovitch, Z. and Montgomery, P.C.: Cyclic AMP in alveolar bone: cellular localization by immunohistochemical methods. J. Dent. Res. 54, L 29, 1975 (abstract, IADR). Shanfeld, J., Mirin, R. and Davidovitch, Z.: In vivo effect of PTH on cAMP and cGMP contents in bone. J. Dent. Res. 55, B303, 1976 (abstract IADR)